Evaporative coolers are commonly used in hot, dry climates to reduce air temperatures. In recent years, these coolers have found commercial acceptance as precoolers for air conditioners, being attached immediately upstream of the refrigeration unit air intake.
Especially in desert areas, water used in the coolers is very hard, containing large quantities of dissolved salts. As the water evaporates, the salts concentrate, and scaling occurs in the tubing, on the walls of the sump, and on the distributive tray and pad of the cooler. Periodic flushing of the system is required to prevent salt accumulation and maintain operating efficiency of the cooler.
A self-flushing device for evaporative coolers is disclosed in Weibert, U.S. Pat. No. 2,828,761, issued Apr. 1, 1958. This device consists of a sump having a siphon reservoir which fills with circulating water when the pump is shut off; water from the pump lines flow by gravity back into the siphon reservoir, filling it to the level of the top of the siphon tube. As the siphon empties the reservoir, water from the main sump flows into the siphon reservoir through a one-way valve. While this device is effective for flushing the system, it requires shutting off the pump to actuate the flushing mechanism.
It is an object of this invention to provide an automatic flushing system for an evaporative cooler which will flush the system according to a predetermined, adjustable schedule and which is easy to clean and service. It is a further object to provide a device which will automatically flush the system whenever the circulating pump is shut off. It is a further object of the invention to provide a cooler sump which requires relatively small amounts of water, conserving water usage and obviating health hazards found in large stagnant bodies of water.